feat: 心跳修复 + 接口测试代理命令(GET_APIS/HTTP_PROXY)

- ws_client: start() 连接改为独立线程，修复心跳线程被阻塞导致 B 端'暂无心跳数据'
- dispatcher: 新增 GET_APIS(返回主程序接口清单) + HTTP_PROXY(代理调用前置机接口)
- main_app_client: 新增 get_apis/http_proxy，自动按 path 加鉴权(/order→Basic, /api/admin→X-Admin-Token)
- config: 新增 order_basic 配置项
- process_guard: 看门狗支持 nssm restart 拉起服务(优先于 start.cmd)

Co-Authored-By: Claude <noreply@anthropic.com>

agent/config.py

@@ -36,6 +36,7 @@ class AgentConfig:
     heartbeat_sec: int
     guard_enabled: bool
     log_dir: str
+    order_basic: str
 
     @classmethod
     def load(cls, conf_path: str = "conf/agent.properties") -> "AgentConfig":
@@ -68,6 +69,7 @@ class AgentConfig:
             heartbeat_sec=int(_get(props, "heartbeat.sec", "15")),
             guard_enabled=_get(props, "guard.enable", "true").lower() == "true",
             log_dir=_get(props, "log.dir", "logs"),
+            order_basic=_get(props, "order.basic", ""),
         )